Distance Formula
Find the distance between the following pairs of points: (i) (2, 3) and (4, 1) (ii) (−5, 7) and (−1, 3) (iii) (a, b) and (−a, −b)
Distance formula: d = √[(x₂ − x₁)² + (y₂ − y₁)²]
(i) Points: (2, 3) and (4, 1)
d = √[(4 − 2)² + (1 − 3)²]
= √[4 + 4] = √8 = 2√2
(ii) Points: (−5, 7) and (−1, 3)
d = √[(−1 − (−5))² + (3 − 7)²]
= √[(4)² + (−4)²]
= √[16 + 16] = √32 = 4√2
(iii) Points: (a, b) and (−a, −b)
d = √[(−a − a)² + (−b − b)²]
= √[(−2a)² + (−2b)²]
= √[4a² + 4b²] = 2√(a² + b²)
Answer: (i) 2√2 (ii) 4√2 (iii) 2√(a² + b²)
